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United States Patent |
5,334,768
|
van Hinsberg
,   et al.
|
August 2, 1994
|
Process for the production of a cycloalkanone and/or a cycloalkanol
Abstract
The invention relates to a process for the preparation of cycloalkanone and
optionally cycloalkanol by causing a mixture containing
cycloalkylhydroperoxide to react with cycloalkene under the influence of a
catalyst, characterised in that the reaction is carried out with a short
measure of cycloalkene relative to the cycloalkylhydroperoxide, under such
conditions that virtually all of the cycloalkene reacts to cycloalkene
oxide and optionally cycloalkanol and/or cycloalkanone, after which the
mixture, optionally after decomposition of cycloalkylhydroperoxide and
distillation of cycloalkane, is subjected to a first separation, in which
cycloalkene oxide--and optionally other components--is separated, after
which the cycloalkene oxide in the separated mixture is isomerised to
substantially cycloalkanone, after which the cycloalkanone obtained--and
optionally cycloalkanol--is recovered.
Inventors:
|
van Hinsberg; Johannes G. (Meerssen, NL);
van de Moesdijk; Cornelis G. M. (Beek, NL);
Spaargaren; Ivo (Geleen, NL);
Sielcken; Otto E. (Sittard, NL)
|
Assignee:
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DSM N.V. (Heerlen, NL)
|
Appl. No.:
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012859 |
Filed:
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February 3, 1993 |
Foreign Application Priority Data
Current U.S. Class: |
568/341; 549/529; 568/342; 568/835 |
Intern'l Class: |
C07C 045/58 |
Field of Search: |
568/342,835,341
549/529
|
References Cited
U.S. Patent Documents
4814511 | Mar., 1989 | Neubauer et al. | 568/342.
|
Foreign Patent Documents |
0192298 | Aug., 1986 | EP | 568/341.
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1337300 | Nov., 1973 | GB | 568/342.
|
Other References
Chemical Abstracts 94: 15288q (1981).
|
Primary Examiner: Reamer; James H.
Attorney, Agent or Firm: Cushman, Darby & Cushman
Claims
We claim:
1. Process for the production of cycloalkanone and optionally cycloalkanol
comprising:
causing a mixture containing cycloalkylhydroperoxide to react with a
cycloalkene under the influence of a catalyst, wherein the reaction is
conducted with a short measure of cycloalkene relative to the
cycloalkylhydroperoxide, under such conditions that virtually all of the
cycloalkene reacts to cycloalkene oxide and optionally cycloalkanol and/or
cycloalkanone,
after which, subjecting the mixture, optionally after decomposition of
cycloalkylhydroperoxide and distillation of cycloalkane, to a first
separation, in which at least cycloalkene oxide is separated therefrom,
isomerizing the cycloalkene oxide in the separated mixture to substantially
cycloalkanone, and
recovering at least the cycloalkanone.
2. Process according to claim 1, wherein the cycloalkylhydroperoxide has
5-12 carbon atoms.
3. Process according to claim 1 wherein the cycloalkene has 5-12 carbon
atoms.
4. Process according to claim 1, wherein the cycloalkylhydroperoxide has
the same number of carbon atoms as the cycloalkene.
5. Process according to claim 4, wherein the cycloalkylhydroperoxide is
cyclohexylhydroperoxide and the cycloalkene is cyclohexene.
6. Process according to claim 1, wherein, optionally after purification,
the mixture obtained after the isomerization is added to the first
separation step with the provisos that the first separation step is a
distillative separation having a bottom stream and the addition is to the
bottom stream, or that mixture is used in a later step in the recovery of
cycloalkanone and/or cycloalkanol.
7. Process according to claim 6, for the preparation of cycloalkanone,
wherein cycloalkanone is recovered in a further distillation step, after
which cycloalkanol is separated from the residue and is converted into
cycloalkanone, which is recirculated and is recovered in the distillative
step.
8. Process according to claim 1, wherein the mixture containing
cycloalkylhydroperoxide contains 5-90 wt. % cycloalkylhydroperoxide.
9. Process according to claim 1, wherein a metal complex is used as a
catalyst and the metal is selected from the group consisting of
molybdenum, tungsten, titanium and vanadium.
10. Process according to claim 1, wherein cycloalkylhydroperoxide is used
in an excess of 5-100 mol. %, relative to the cycloalkene.
11. Process according to claim 1, wherein the isomerization of cycloalkene
oxide takes place in the gas phase.
12. Process according to claim 1, wherein the isomerization takes place
under the influence of a precious metal catalyst.
Description
The invention relates to a process for the production of cycloalkanone and
optionally cycloalkanol by causing a mixture containing
cycloalkylhydroperoxide to react with a cycloalkene under the influence of
a catalyst.
Such a process is described for cyclohexane and cyclohexene in EP-A-268826.
According to the process described therein virtually all the
cyclohexylhydroperoxide, which is formed by oxidation of cyclohexane,
reacts with a portion of the cyclohexene to form cyclohexene oxide or
cyclohexane epoxide. Because of this, unreacted cyclohexene remains in the
reaction mixture, which is hydrogenated to cyclohexane in a later step.
The epoxide is also hydrogenated to cyclohexanol. A drawback of this
process is that the cyclohexene is not optimally used and moreover--if
cyclohexanone in particular is the desired end product--all the
cyclohexanol must be dehydrogenated to cyclohexanone.
The invention provides a process for the production of cycloalkanone and
optionally cycloalkanol that does not present the above drawback.
This aim is achieved because the invention provides a process for the
production of cycloalkanone and optionally cycloalkanol by causing a
mixture containing cycloalkylhydroperoxide to react with a cycloalkene,
under the influence of a catalyst, which reaction is carried out with a
short measure of cycloalkene relative to the cycloalkylhyroperoxide, under
such conditions that virtually all the cycloalkene reacts to cycloalkene
oxide and optionally cycloalkanol and/or cycloalkanone, after which,
optionally after decomposition of cycloalkylhydroperoxide and distillation
of cycloalkane, the mixture is subjected to a first distillative
separation, in which cycloalkene oxide--and optionally other
components--is separated, after which the cycloalkene oxide in the
separated mixture is isomerised to substantially cycloalkanone, after
which the cycloalkanone obtained--and optionally cycloalkanol--is
recovered.
Optionally, the mixture obtained after isomerisation may, optionally after
purification, be added to the bottom stream of the first distillative
separation or may be used in another step in the recovery of cycloalkanone
and/or cycloalkanol.
The advantages of the invention are exploited even more if the process
according to the invention is used for the production of cycloalkanone, in
which cycloalkanone is recovered in a further distillation step, after
which cycloalkanol is separated from the residue and is converted into
cycloalkanone, which is recirculated and is recovered in the
aforementioned distillation step.
With the process according to the invention full advantage is taken of the
saturation state of cycloalkene and hence hydrogenation steps and/or
dehydrogenation steps as described in EP-A-268826, which are in principle
unnecessary, are avoided.
Preferably, the cycloalkylhydroperoxide has 5-12 carbon atoms, more in
particular 6, 8 or 12. The cycloalkene preferably has 5-12 carbon atoms,
more in particular 6, 8 or 12. The process can be carried out in a
preferred embodiment, according to which the cycloalkylhydroperoxide and
the cycloalkene have the same number of carbon atoms. According to another
preferred embodiment cyclohexylhydroperoxide is chosen as
cycloalkylhydroperoxide and cyclooctene or cyclododecene is chosen as
cycloalkene. For the sake of simplicity, in the following text of this
patent the invention will be described more in particular on the basis of
cyclohexane/cyclohexene because that appears to present an additional
advantage, namely that the process according to the invention links up
with cyclohexane oxidation processes used in existing plants.
Cyclohexylhydroperoxide is preferably produced in a known manner through
oxidation of cyclohexane. The peroxide can be produced in a favourable
manner in (preferably a series of) reactors, to which air is supplied at a
temperature of between 140.degree. and 250.degree. C. and a pressure of
between 0.4 and 2 MPa (4-20 bar), preferably in the absence of a metal
catalyst. The resulting product is often a mixture containing 1-8 wt. %,
preferably 2-6 wt. %, cyclohexylhydroperoxide and some cyclohexanone,
cyclohexanol and byproducts.
The cyclohexene can be produced in a favourable way in a manner known per
se through the partial hydrogenation of benzene. It is not necessary to
use pure cyclohexene; solutions of 10-60 wt. % in an organic medium
(preferably cyclohexane) are very suitable.
To ensure that the epoxidation takes place at a sufficiently high rate and
to prevent the necessity of using undesirably large reactor volumes it is
preferable to use 5-90% cycloalkylhydroperoxide mixtures. To this end
cycloalkane can easily be evaporated from the hydroperoxide, optionally
after washing with for example water. Optionally, an alcohol such as
cyclohexanol may be added to for example cyclohexylhydroperoxide so that
virtually all the cyclohexane can be removed via distillation. Preferably,
the cycloalkylhydroperoxide used is a 10-80 wt. %, and more in particular
a 15-70 wt. %, solution in an organic solvent.
The epoxidation reaction between the cyclohexylhydroperoxide and
cyclohexene takes place under the influence of a catalyst at a temperature
between 0.degree. and 150.degree. C., preferably between 20.degree. and
120.degree. C. The pressure is not critical; atmospheric pressure is
advantageous because it involves a simple setup. Higher pressures are also
possible, for example pressures of up to 2 MPa (20 bar),
As catalyst use is made of a homogeneous or heterogeneous metal-containing
compound with sufficient activity for the epoxidation reaction. Very
suitable metals are molybdenum, tungsten, titanium and vanadium.
Molybdenum complexes are preferable because of their high activity. The
catalysts are used in amounts of between 0.001 and 5 wt. % relative to the
reaction mixture.
The epoxidation reaction is carried out using an excess amount of
cycloalkylhydroperoxide. The excess is usually more than 5 mol. % relative
to the cycloalkene. In principle the upper limit is not critical, but the
excess peroxide has to be recirculated or decomposed to cycloalkanol or
cycloalkanone. It is hence preferable to use an excess amount of less than
100 mol. %. Excess amounts of between 10 and 50 mol. % are particularly
preferable because they enable optimum reaction times and optimum
efficient use of the peroxide.
The epoxidation reaction is preferably continued until virtually all of the
cycloalkene is converted. As a rule, less than 3 wt. % cycloalkene will
remain unreacted, preferably less than 2%, in particular less than 1%.
After the epoxidation reaction the reaction mixture is optionally first
subjected to a cycloalkylhydroperoxide decomposition step. As a rule,
processes for the preparation of cyclohexanone from cyclohexane already
include such a decomposition step; it can be carried out with the aid of
heterogeneous or homogeneous metal-containing catalysts (see e.g.
DE-A-3222144, U.S. Pat. No. 4,503,257, U.S. Pat. No. 4,482,746,
EP-A-270468 and EP-A-367326).
After this optional decomposition step the mixture is optionally subjected
to washing with water, a bicarbonate solution or a sodium hydroxide
solution, as is common in known processes for the preparation of
cyclohexanone from cyclohexane. It has been found that if the reaction
mixture is not exposed to water or a bicarbonate solution for longer than
necessary virtually all of the cyclohexene oxide remains in the organic
phase and a negligible amount decomposes or reacts.
After that, cycloalkane may optionally be removed
through--preferably--distillative separation and other purification steps
may optionally be carried out.
A next essential step is the isomerisation of cycloalkene oxide to
substantially cycloalkanone. To this end cycloalkene oxide is first
separated from the reaction mixture; this cycloalkene oxide may optionally
contain 5-50 wt. % cycloalkane and/or other components. The separation is
preferably effected through distillation, in which the cycloalkene oxide
and other so-called light components are separated from cycloalkanol and
cycloalkanone and heavier components. The isomerisation is preferably
effected in the gas phase. Very suitable is for example the process
described in EP-A-192298. The isomerisation preferably takes place under
the influence of a precious metal catalyst (Pd or Pt in particular Pd) in
the presence of hydrogen. Basic .gamma.-alumina is preferably used as a
carrier for the precious metal, the amount of precious metal being 0.5-5
wt. % relative to the carrier. The temperature is preferably between
140.degree. and 250.degree. C., more in particular between 175.degree. and
225.degree. C. The pressure is not critical; the partial hydrogen pressure
is preferably between 1 and 1000 kPa.
Other processes for the isomerisation of cycloalkene oxide to cycloalkanone
may however also be used.
The entire mixture obtained may be fed to the bottom stream from which the
cycloalkene oxide has been removed (the main process stream), from which
cycloalkanone is then recovered.
It is also possible to purify the isomerisation mixture first, separating
for example only the components that are lighter than cycloalkanol and
cycloalkanone, and then feed the remaining mixture to the process at a
suitable point in the process. It is also possible to recover
cycloalkanone directly from the isomerisation mixture.
It is preferable to return the isomerisation mixture to the main process
stream, optionally after partial purification, and to recover
cycloalkanone from said main process stream in the known manner and then
dehydrogenate cycloalkanol to cycloalkanone and return the
cycloalkanone-containing mixture thus obtained to the process at a
suitable point in the process.
The process will be further elucidated with reference to two figures and
examples, without being limited thereto.
FIG. 1 shows a diagram of a preferred embodiment of the process.
FIG. 2 is an example of an epoxidation reactor.
In FIG. 1 (1) is a cyclohexane stream that is oxidized with air (2) in
reactors (A). The resulting oxidized cyclohexane contains 1-8 wt. %
cyclohexylhydroperoxide. In (B) this stream is partially stripped of
cyclohexane (4), which is recirculated to (1). The resultant mixture (5)
preferably contains 10-40 wt. % cyclohexylhydroperoxide. The epoxidation
takes place in (C); stream (6) contains cyclohexene. The resultant
reaction mixture (7) containing cyclohexene oxide and excess
cyclohexylhydroperoxide is subjected to a cyclohexylhydroperoxide
decomposition step in (D) for example by passing it over a heterogeneous
decomposition catalyst. Then the reaction mixture (8) is washed with
bicarbonate or water (9) in (E) and is thus stripped of acid byproducts.
In (F) cyclohexane is distilled from the process stream. The cyclohexane
(11) is returned to (1). A process stream containing cyclohexene oxide
(13) is separated from the process stream containing cyclohexanol and
cyclohexanone (17) by means of distillation. Cyclohexene oxide is
isomerised in (H) to obtain predominantly cyclohexanone. Light components
are separated from this cyclohexanone-containing mixture (14) in (I). The
light components may be burned to generate energy. The
cyclohexanone-containing process stream (16) is fed to the bottom stream
(17) of the cyclohexene oxidation distillation step (G) and cyclohexanone
(18) is separated from that stream. This cyclohexanone may optionally be
subjected to an additional purification step. Cyclohexanol (21) is
separated from the heavy components (20) in the bottom stream (19) of the
cyclohexanone distillation step (J). The heavy components can be burned or
worked up. The cyclohexanol (21) is dehydrogenated in (L). Normally, the
dehydrogenation is not complete and the resultant mixture (22) of
cyclohexanone and cyclohexanol is returned to process stream (17) or
process stream (12) (not indicated).
FIG. 2 shows an example of a multistage fixed-bed reactor, in which bed
sections (A), (C), (E), (G) and (I) contain the epoxidation catalyst on a
carrier. (B), (D), (F) and (H) are sections where the process streams are
mixed, for example in a static mixer. The
cyclohexylhydroperoxide-containing process stream (1) is split up into
several streams (3-10); all of the cyclohexene (2) is fed directly to the
reactor. By now using excess cyclohexene in the first 4 bed sections and
using an excess of cyclohexylhydroperoxide in the last bed section only,
cyclohexene is virtually completely converted into cyclohexene oxide in a
relatively short time.
A possible distribution of the streams in FIG. 2, in the case of for
example a 25% excess of cyclohexylhydroperoxide, is:
______________________________________
stream 1: 100 parts of cyclohexylhydroperoxide
2: 80 parts of cyclohexene
3: 40 parts of cyclohexylhydroperoxide
4: 60 parts of cyclohexylhydroperoxide
5: 20 parts of cyclohexylhydroperoxide
6: 40 parts of cyclohexylhydroperoxide
7: 10 parts of cyclohexylhydroperoxide
8: 30 parts of cyclohexylhydroperoxide
9: 5 parts of cyclohexylhydroperoxide
10: 25 parts of cyclohexylhydroperoxide
______________________________________
In this way cyclohexene reacts in a 2:1 excess in the first 4 reactor
sections and in the last reactor section cyclohexylhydroperoxide is
present in a 5-fold excess relative to the cyclohexene still present
there. The resulting reaction mixture (11) then still contains 20 parts of
cyclohexylhydroperoxide in addition to cyclohexanol, cyclohexanone and
cyclohexene oxide.
Such a concept is also very suitable if the epoxidation takes place under
the influence of a homogeneous catalyst; in that case use can preferably
be made of a series of stirred reactors.
EXAMPLE I
A reaction mixture consisting of 1 mol. % molybdenum on a carrier, 15.2
mmol cyclohexene, 18.7 mmol cyclohexylhydroperoxide, 9.7 mmol
cyclohexanol, 3.8 mmol cyclohexanone and 28.8 mmol cyclohexane was heated
to 80.degree. C. for 3 hours. After this period the reaction mixture
contained virtually no cyclohexene (0.12 mmol ), 1.51 mmol
cyclohexylhydroperoxide, 14.78 mmol cyclohexene oxide, 5.45 mmol
cyclohexanone, 25.26 mmol cyclohexanol and 28.8 mmol cyclohexane. For this
reaction use was made of a solution of cyclohexylhydroperoxide
concentrated to 40% that was obtained through uncatalysed air oxidation of
cyclohexane and a 60% solution of cyclohexene in cyclohexane.
The resultant reaction mixture was maintained at 70.degree. C. for half an
hour after the addition of cobalt acetate to allow the remaining
cyclohexylhydroperoxide to decompose to cyclohexanol and cyclohexanone.
The resulting reaction mixture was washed for 30 seconds using 1:1
Vol./Vol. 0.95M NaHCO.sub.3 in water. GC analysis showed that only about
0.5% epoxide had disappeared from the organic layer. Acid byproducts and
byproducts that readily dissolve in water were removed in this washing.
Then cyclohexane was distilled off; the resultant reaction mixture
contained 10 wt. % cyclohexanone, 54 wt. % cyclohexanol and 36 wt. %
cyclohexene oxide. Cyclohexene oxide was distilled off at about
130.degree. C. This stream was isomerised in the gas phase as described in
example I of EP-A-192298; by using a 3x larger catalyst bed it was ensured
that the degree of conversion of the cyclohexene oxide remained above 95%.
The resulting isomerisation mixture contained cyclohexanone and
cyclohexanol in a ratio of 4:1.
EXAMPLE II
In the same way as in example I a 40% solution of cyclohexene in
cyclohexane was epoxidized with cyclohexylhydroperoxide (40%) using 0.2
mol. % molybdenum-bis-acetylacetonate as a homogeneous catalyst (20%
excess cyclohexylhydroperoxide). The results were more or less the same as
those obtained in example I.
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